1. Field of the Invention
The present invention relates to a method for testing a supply circuit for at least one ignition circuit.
2. Description of the Related Art
Occupant protection systems have an ignition circuit configuration that has at least one ignition circuit for activating restraint means. The energy used to activate these restraint means is generally provided from an energy accumulator and/or from a vehicle electrical system that includes an alternator and at least one battery. This means that, when the engine is running, the energy accumulator and/or the alternator and, when the engine is idling, the energy accumulator and/or the battery provide(s) the energy required for activating the restraint means. The ignition circuit configuration for the various restraint means generally includes two circuit blocks that each have a semiconductor output stage and a corresponding driver and/or control circuit. In this case, a high-side ignition circuit is looped into an energy supply line, and the low-side ignition circuit is looped into the feedback line. To enhance the security of the ignition circuit configuration, another semiconductor output stage can be looped centrally into the energy supply line of the high-side ignition circuit.
What are commonly known as semiconductor output stages are generally constituted of power transistors designed as power MOSFETs, each having a source-drain (reverse) diode. To minimize the risk of a false activation, particularly in the case of a supply voltage short circuit in the ignition circuit in the starting phase, the energy accumulator and/or the vehicle system voltage are/is coupled to the ignition circuits in a manner that provides reverse-polarity protection.